1. Field of the Invention
The present invention relates to valves for controlling fluids. More particularly, the present invention relates to valves which control the flow of fluids in flexible tubing by pinching, the tube closed to prevent flow.
2. Description of the Prior Art
Pinch valves control are used with flexible tubing such as surgical tubing or plastic tubing where there is a requirement to isolate the fluid flowing in the valve from the valve components. This tubing must be flexible and resilient. It is required that the tubing can be pinched to an extent that all flow in the tubes is stopped. Further, the tubing must have properties that cause a return to a pre-pinch shape. To be efficient the tubing must be capable of withstanding multiple pinches without damaging effects. Simple pinch valves are found in the art, however, what is needed is a pinch valve which is operable by a controller in an automatic system. A further need is for a pinch valve that operates with minimum power. It is desirable that the valve be installable on tubing already in place without the need for passing an end of the tubing through the valve.
Numerous innovations for Improved Pinch Valve Assembly have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present invention as hereinafter contrasted.
In U.S. Pat. No. 5,190,071, titled Pinch Valve Assembly, invented by Akos Sule, a pinch valve assembly includes a valve body in which a plunger is spring loaded against a portion of a flexible tube which passes through the valve body. The plunger causes the flexible tube to collapse preventing flow through the tube. Energization of a solenoid which is mounted on the valve body causes the plunger to release the tube, permitting flow. In an alternative embodiment, energization of the solenoid causes the plunger to bear on the flexible tube thereby providing a normally open valve arrangement. In another alternative embodiment the plunger bears on a plurality of flexible tubes thereby facilitating simultaneous control of different fluids. In still another alternative embodiment the plunger is mounted in roller bearings and the top of the plunger bears on an electrical switch contact which provides an electrical verification of the open or closed state of the pinch valve assembly.
In U.S. Pat. No. 4,230,151, titled Pinch Valve, invented by Ulf R. S. Jonsson, a pinch valve for controlling the flow through at least two flexible hoses includes an actuating member by which one hose is pinched against an abutment. This abutment is yieldable against a spring bias and normally keeps the other hose pinched. When said one hose has been pinched, the abutment is moved against the spring bias by the actuating member in order to relieve said other hose.
In U.S. Pat. No. 3,823,724, titled Controlling Flow of Medical Fluids, invented by William P. Davis, a medical pinch valve is described having an actuator, a spring loaded plunger and a valving arm which collapses an array of channel-contained medical tubing with memory at a selected site. When open, the memory of the tubing and the pressure of the medical fluid opens the previously occluded site to permit flow. Hence, flow of medical fluid from source to destination sites is facilitated. Only the tubing is sterilized and tubing removal and replacement is rapidly achieved so that "down time" is virtually non-existent.
The above patented inventions differ from the present invention because they fail to describe or claim at least a combination of the following features depicted in the present invention a constant power solenoid combined with a fixed dowel pin spacing.
Numerous innovations for Improved Pinch Valve Assembly have been provided in the prior art that are adapted to be used. Even though these innovations may be suitable for the specific individual purposes to which they address, they would not be suitable for the purposes of the present invention as heretofore described.